The London mayor blamed "coalition politics" for watering down the previous regime of control orders and claimed the current terrorism prevention and investigation measures or "Tpims" were not working.

He urged the home secretary, Theresa May, to "get tough" with the Liberal Democrats to end the "ludicrous" situation.

"If a fellow can get into a burqa and evade his invigilators in the way that Mr Mohamed has done, then we clearly need to look at how they are working," Johnson told LBC 97.3 radio.

"Depending on how much risk you are deemed to pose, you should be deprived of contact with networks that might help you with any end you desire. This guy Mohamed was obviously helped to escape. I don't believe for a minute that he did it on his own. He was in contact with people who are sympathisers. Characters such as him – and even if he doesn't pose an immediate threat to this country, it is plain he is a danger – should be more closely invigilated than they currently are and I am sure that is a point that Theresa May will be taking up."

Johnson's comments came as it emerged that Scotland Yard counter-terrorism officers have been in touch with their counterparts in the West Midlands. A source in the Somali community in Small Heath, Birmingham, told the Birmingham Evening Mail: "I know of a respected elder in the community who is in contact with the local counter-terror unit and says he was contacted by an officer on Sunday before the news went public. He got the impression the fugitive has friends in Birmingham who are involved with [Somali Islamist group] al-Shabaab and he may even have family in the city." Scotland Yard have confirmed that they have been in contact with counter-terrorism units across Britain in the course of their manhunt.

The home secretary has defended the use of Tpims after Mohamed's disappearance from a mosque in Acton, west London, on Friday. She has told MPs that although he did not represent a direct threat to the British public, the Tpim had been imposed to stop him travelling overseas to support terrorism.

Mohamed, 27, is a British citizen and is the second suspect on a Tpim order to go missing in the last year. The first, Ibrahim Magag, disappeared off the security service's radar after he ripped off his tracking tag and jumped into a black cab in Camden Town, north London.

Mohamed went missing only hours after an Old Bailey prosecution against him for tampering with his electronic tag was discontinued when the crown offered no evidence. The home secretary insisted, however, that there were no issues with the operation of his tag in his disappearance.

May said Mohamed has been linked with al-Shabaab, and is believed to have helped various individuals to travel from Britain to Somalia to engage in terrorism-related activity.

The Metropolitan police counter-terrorism command has launched an intensive hunt. Mohamed's photograph and details have been circulated to all ports and airports. May said the police held his UK passport.

She defended the Tpims regime, saying its abscondence record was little different to that of the control-order regime, which it replaced last year, under which seven terror suspects disappeared in six years.